Freeman l



(No Model.)

F. L. TWISS. 0AM MOTION FOR TYPE WRITING MACHINES.

No. 408,150. Patented July 3-0, 1889.

WITNESSES: A INVENTDR M i N. PETERS, Phm-Lnhc u lwr. Washinglon. I) CUNTTED STATES PATENT OFFICE.

FREEMAN L. TNVISS, OF GROTON, NE\V YORK, ASSIGNOR TO THE CRANDALLTYPE-VRITER COMPANY, OF SAME PLACE.

CAM-MCTION FQR TYPE-WRITING MACHINES.

SPECIFICATION forming part of Letters Patent No. 408,150, dated July 30,1889.

Application filed January 9, 1888. Serial No. 260,157. (No model.)

To aZZ whom it may concern.-

Be it known that I, FREEMAN L. Twiss, of Groton, in the county ofTompkins, in the State of New York, have invented new and usefulImprovements in Cam-Motions for Typeritin g Machines, of which thefollowing, taken in connection with the accompanying drawings, is afull, clear, and exact description.

This invention relates to animprovement in cam-motions for type-writers;and it consists in certain peculiarities of the construction andoperation of the same, substantially as will be hereinafter more fullyset forth and claimed.

In order to enable others skilled in the art to which my inventionpertains to make and use the same, I will now proceed to describe itsconstruction and operation, referring to the accompanying drawings inwhich Figure 1 is a longitudinal vertical section of a part of the frameof a type-writer, showing the parts of my invention as they are whennormal and at rest. Fig. 2 is a similar view showing the position of theparts after the strokeis finished or at the end of the forward stroke;and Fig. 3 is a vertical cross-section of the main frame, showing theactuating parts in elevation. But one key and its accompanying devicesis shown in any View; but it will be understood that this is forclearness, and that as many keys will be used as are desirable, and thatall will be simply a duplicate of the one herein shown.

My invention relates to that class of typewriters in which there is atype-cylinder carried upon a pivoted arm and thrown forward against theimpression-cylinder when the key is depressed; and my object is to soconstruct the moving parts interposed between the key and thetype-cylinder that the initial movement of this cylinder will be quiteslow and easily operated and its motion increased gradually in speed asthe inertia is overcome, and at the end oft its stroke deliver theimpression at proper speed and force to make it clear and plain, andalso to prevent any recoil of the type-cylinder after delivering itsblow till the pressure is removed from the key. All this I accomplish asfollows:

a represents the main frame of a typewriter of any desired and suitableform, and a is one of the pivoted key-levers. This will of course beshaped to lit the particular machine in which it is used, but is hereinshown as a plain pivoted bar, which serves everypurpose of this case.

The type-cylinder Z) is held in a yoke 11, pivoted to a bracket on themain frame, and all these parts are made and used as has been usual inthis class of machine, and therefore do not require any furtherdescription herein.

In proper supporting standards or brackets c on the base of the machineI journal a rockshaft 0, on which is secured a yoke 0 resting upon therear end of the key-lever, and lifted thereby to rock the shaft when thekey is 0perated, as will be clearly seen in the drawings. Upon thisrock-shaft is also secured a camfaeed arm d, having a shallow notch clin its end, which arm lies normally in contact with an arm 6, secured tothe yoke or pivoted frame which carries the type-cylinder. This latterarm is provided with a pin 6, for engagement with the notched end of thecam-arm d, and is also formed with an inclined face or bearing-surface 6for contact with the face of the cam.

By reference to Fig. 1 it will be seen that the parts lie normally withthe type-cylinder thrown back, and the pin 6' in engagement with thenotched cam-arm. \Vhen the key is depressed by the operator, the rearend of the key-lever rises andlifts the yoke 0 rocking the shaft 0 inits bearings. This throws back the cam-arm, and as it bears against thearm 6 the latter is also forced back, rocking the yoke b and throwingthe type-cylinder forward.

It will be noted that the normal bearingsurface of the cam-arm is nearlystraight, and is formed with a gradually-quickening curve from thispoint to its end. This peculiar formation starts the type-cylinderforward very slowly; but the motion is increased as the curved surfaceof the cam is brought into 5 use till the end of the stroke is madequickly, and with a force sufficient to form a proper impression, and atthe end of the stroke the parts assume the position of Fig. 2, where itwill be seen that the pin (1 has passed out of the notched end of thecam-arm and lies behind it. The end of the cam therefore lies betweenthis pin and the inclined face of the arm 8, and forms a sufficientlyrigid connection to prevent. any recoil of the type-cylinder on makingthe impression. As soon as pressure is removed from the key, the partsfall back to their normal position, as seen in Fig. 1.

As before stated, the drawings herewith 'show but one key; but all thekeys necessary for use will be similarly fitted.

The gradual starting of the type-cylinder and its quick finish make theoperation of the key very easy and of even force throughout, as butlittle force is needed to overcome the inertia of the cylinder at lowspeed, while the change of bearing upon the face of the cam while inmotion produces the increased speed, and as it at the same time givesthe key a correspondingly-increasing leverage no additional pressure isneeded to operate it, and the force applied is even and regular throughthe whole stroke.

Having thus fully described my invention,

what I claim as new, and desire to secure by Letters Patent, is

1. In a typewriter, the combination, with a type-cylinder and a pivotedyoke for carrying said cylinder, provided with a stop-pin and aninclined bearing-face, of a cam-arm having its face formed with agradually-increasing curve, and its end adapted to lie between thestop-pin and inclined bearing-face'at the end of the stroke to preventrecoil, substantially as and for the purpose set forth.

2. In a type-writer, the combination, with the main frame a, key-levera, type-cylinder b, and its pivoted carrier 1), provided with the arm 8,having the bearing-face e and pin 6', of the rock-shaft 0, its yoke cand the notched cam-faced arm (Z, all constructed and arranged tooperate substantially as and for the purpose set forth.

In testimony whereof I have hereunto signed my name, in the presence oftwo attesting Witnesses, at Groton, in the county of Tompkins, in theState of New York, this 24th dayof December, 1887.

FREEMAN L. TWISS.

W'itnesses:

FLORA RHODES, D. H. MARSH.

